refs.con commit Merge branch 'jl/status-ignore-submodules' (a76b208)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5#include "dir.h"
   6
   7/* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8#define REF_KNOWS_PEELED 04
   9#define REF_BROKEN 010
  10
  11struct ref_list {
  12        struct ref_list *next;
  13        unsigned char flag; /* ISSYMREF? ISPACKED? */
  14        unsigned char sha1[20];
  15        unsigned char peeled[20];
  16        char name[FLEX_ARRAY];
  17};
  18
  19static const char *parse_ref_line(char *line, unsigned char *sha1)
  20{
  21        /*
  22         * 42: the answer to everything.
  23         *
  24         * In this case, it happens to be the answer to
  25         *  40 (length of sha1 hex representation)
  26         *  +1 (space in between hex and name)
  27         *  +1 (newline at the end of the line)
  28         */
  29        int len = strlen(line) - 42;
  30
  31        if (len <= 0)
  32                return NULL;
  33        if (get_sha1_hex(line, sha1) < 0)
  34                return NULL;
  35        if (!isspace(line[40]))
  36                return NULL;
  37        line += 41;
  38        if (isspace(*line))
  39                return NULL;
  40        if (line[len] != '\n')
  41                return NULL;
  42        line[len] = 0;
  43
  44        return line;
  45}
  46
  47static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  48                                int flag, struct ref_list *list,
  49                                struct ref_list **new_entry)
  50{
  51        int len;
  52        struct ref_list *entry;
  53
  54        /* Allocate it and add it in.. */
  55        len = strlen(name) + 1;
  56        entry = xmalloc(sizeof(struct ref_list) + len);
  57        hashcpy(entry->sha1, sha1);
  58        hashclr(entry->peeled);
  59        memcpy(entry->name, name, len);
  60        entry->flag = flag;
  61        entry->next = list;
  62        if (new_entry)
  63                *new_entry = entry;
  64        return entry;
  65}
  66
  67/* merge sort the ref list */
  68static struct ref_list *sort_ref_list(struct ref_list *list)
  69{
  70        int psize, qsize, last_merge_count, cmp;
  71        struct ref_list *p, *q, *l, *e;
  72        struct ref_list *new_list = list;
  73        int k = 1;
  74        int merge_count = 0;
  75
  76        if (!list)
  77                return list;
  78
  79        do {
  80                last_merge_count = merge_count;
  81                merge_count = 0;
  82
  83                psize = 0;
  84
  85                p = new_list;
  86                q = new_list;
  87                new_list = NULL;
  88                l = NULL;
  89
  90                while (p) {
  91                        merge_count++;
  92
  93                        while (psize < k && q->next) {
  94                                q = q->next;
  95                                psize++;
  96                        }
  97                        qsize = k;
  98
  99                        while ((psize > 0) || (qsize > 0 && q)) {
 100                                if (qsize == 0 || !q) {
 101                                        e = p;
 102                                        p = p->next;
 103                                        psize--;
 104                                } else if (psize == 0) {
 105                                        e = q;
 106                                        q = q->next;
 107                                        qsize--;
 108                                } else {
 109                                        cmp = strcmp(q->name, p->name);
 110                                        if (cmp < 0) {
 111                                                e = q;
 112                                                q = q->next;
 113                                                qsize--;
 114                                        } else if (cmp > 0) {
 115                                                e = p;
 116                                                p = p->next;
 117                                                psize--;
 118                                        } else {
 119                                                if (hashcmp(q->sha1, p->sha1))
 120                                                        die("Duplicated ref, and SHA1s don't match: %s",
 121                                                            q->name);
 122                                                warning("Duplicated ref: %s", q->name);
 123                                                e = q;
 124                                                q = q->next;
 125                                                qsize--;
 126                                                free(e);
 127                                                e = p;
 128                                                p = p->next;
 129                                                psize--;
 130                                        }
 131                                }
 132
 133                                e->next = NULL;
 134
 135                                if (l)
 136                                        l->next = e;
 137                                if (!new_list)
 138                                        new_list = e;
 139                                l = e;
 140                        }
 141
 142                        p = q;
 143                };
 144
 145                k = k * 2;
 146        } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 147
 148        return new_list;
 149}
 150
 151/*
 152 * Future: need to be in "struct repository"
 153 * when doing a full libification.
 154 */
 155static struct cached_refs {
 156        char did_loose;
 157        char did_packed;
 158        struct ref_list *loose;
 159        struct ref_list *packed;
 160} cached_refs;
 161static struct ref_list *current_ref;
 162
 163static struct ref_list *extra_refs;
 164
 165static void free_ref_list(struct ref_list *list)
 166{
 167        struct ref_list *next;
 168        for ( ; list; list = next) {
 169                next = list->next;
 170                free(list);
 171        }
 172}
 173
 174static void invalidate_cached_refs(void)
 175{
 176        struct cached_refs *ca = &cached_refs;
 177
 178        if (ca->did_loose && ca->loose)
 179                free_ref_list(ca->loose);
 180        if (ca->did_packed && ca->packed)
 181                free_ref_list(ca->packed);
 182        ca->loose = ca->packed = NULL;
 183        ca->did_loose = ca->did_packed = 0;
 184}
 185
 186static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 187{
 188        struct ref_list *list = NULL;
 189        struct ref_list *last = NULL;
 190        char refline[PATH_MAX];
 191        int flag = REF_ISPACKED;
 192
 193        while (fgets(refline, sizeof(refline), f)) {
 194                unsigned char sha1[20];
 195                const char *name;
 196                static const char header[] = "# pack-refs with:";
 197
 198                if (!strncmp(refline, header, sizeof(header)-1)) {
 199                        const char *traits = refline + sizeof(header) - 1;
 200                        if (strstr(traits, " peeled "))
 201                                flag |= REF_KNOWS_PEELED;
 202                        /* perhaps other traits later as well */
 203                        continue;
 204                }
 205
 206                name = parse_ref_line(refline, sha1);
 207                if (name) {
 208                        list = add_ref(name, sha1, flag, list, &last);
 209                        continue;
 210                }
 211                if (last &&
 212                    refline[0] == '^' &&
 213                    strlen(refline) == 42 &&
 214                    refline[41] == '\n' &&
 215                    !get_sha1_hex(refline + 1, sha1))
 216                        hashcpy(last->peeled, sha1);
 217        }
 218        cached_refs->packed = sort_ref_list(list);
 219}
 220
 221void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 222{
 223        extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 224}
 225
 226void clear_extra_refs(void)
 227{
 228        free_ref_list(extra_refs);
 229        extra_refs = NULL;
 230}
 231
 232static struct ref_list *get_packed_refs(void)
 233{
 234        if (!cached_refs.did_packed) {
 235                FILE *f = fopen(git_path("packed-refs"), "r");
 236                cached_refs.packed = NULL;
 237                if (f) {
 238                        read_packed_refs(f, &cached_refs);
 239                        fclose(f);
 240                }
 241                cached_refs.did_packed = 1;
 242        }
 243        return cached_refs.packed;
 244}
 245
 246static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 247{
 248        DIR *dir = opendir(git_path("%s", base));
 249
 250        if (dir) {
 251                struct dirent *de;
 252                int baselen = strlen(base);
 253                char *ref = xmalloc(baselen + 257);
 254
 255                memcpy(ref, base, baselen);
 256                if (baselen && base[baselen-1] != '/')
 257                        ref[baselen++] = '/';
 258
 259                while ((de = readdir(dir)) != NULL) {
 260                        unsigned char sha1[20];
 261                        struct stat st;
 262                        int flag;
 263                        int namelen;
 264
 265                        if (de->d_name[0] == '.')
 266                                continue;
 267                        namelen = strlen(de->d_name);
 268                        if (namelen > 255)
 269                                continue;
 270                        if (has_extension(de->d_name, ".lock"))
 271                                continue;
 272                        memcpy(ref + baselen, de->d_name, namelen+1);
 273                        if (stat(git_path("%s", ref), &st) < 0)
 274                                continue;
 275                        if (S_ISDIR(st.st_mode)) {
 276                                list = get_ref_dir(ref, list);
 277                                continue;
 278                        }
 279                        if (!resolve_ref(ref, sha1, 1, &flag)) {
 280                                hashclr(sha1);
 281                                flag |= REF_BROKEN;
 282                        }
 283                        list = add_ref(ref, sha1, flag, list, NULL);
 284                }
 285                free(ref);
 286                closedir(dir);
 287        }
 288        return sort_ref_list(list);
 289}
 290
 291struct warn_if_dangling_data {
 292        FILE *fp;
 293        const char *refname;
 294        const char *msg_fmt;
 295};
 296
 297static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 298                                   int flags, void *cb_data)
 299{
 300        struct warn_if_dangling_data *d = cb_data;
 301        const char *resolves_to;
 302        unsigned char junk[20];
 303
 304        if (!(flags & REF_ISSYMREF))
 305                return 0;
 306
 307        resolves_to = resolve_ref(refname, junk, 0, NULL);
 308        if (!resolves_to || strcmp(resolves_to, d->refname))
 309                return 0;
 310
 311        fprintf(d->fp, d->msg_fmt, refname);
 312        return 0;
 313}
 314
 315void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 316{
 317        struct warn_if_dangling_data data;
 318
 319        data.fp = fp;
 320        data.refname = refname;
 321        data.msg_fmt = msg_fmt;
 322        for_each_rawref(warn_if_dangling_symref, &data);
 323}
 324
 325static struct ref_list *get_loose_refs(void)
 326{
 327        if (!cached_refs.did_loose) {
 328                cached_refs.loose = get_ref_dir("refs", NULL);
 329                cached_refs.did_loose = 1;
 330        }
 331        return cached_refs.loose;
 332}
 333
 334/* We allow "recursive" symbolic refs. Only within reason, though */
 335#define MAXDEPTH 5
 336#define MAXREFLEN (1024)
 337
 338static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 339{
 340        FILE *f;
 341        struct cached_refs refs;
 342        struct ref_list *ref;
 343        int retval;
 344
 345        strcpy(name + pathlen, "packed-refs");
 346        f = fopen(name, "r");
 347        if (!f)
 348                return -1;
 349        read_packed_refs(f, &refs);
 350        fclose(f);
 351        ref = refs.packed;
 352        retval = -1;
 353        while (ref) {
 354                if (!strcmp(ref->name, refname)) {
 355                        retval = 0;
 356                        memcpy(result, ref->sha1, 20);
 357                        break;
 358                }
 359                ref = ref->next;
 360        }
 361        free_ref_list(refs.packed);
 362        return retval;
 363}
 364
 365static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 366{
 367        int fd, len = strlen(refname);
 368        char buffer[128], *p;
 369
 370        if (recursion > MAXDEPTH || len > MAXREFLEN)
 371                return -1;
 372        memcpy(name + pathlen, refname, len+1);
 373        fd = open(name, O_RDONLY);
 374        if (fd < 0)
 375                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 376
 377        len = read(fd, buffer, sizeof(buffer)-1);
 378        close(fd);
 379        if (len < 0)
 380                return -1;
 381        while (len && isspace(buffer[len-1]))
 382                len--;
 383        buffer[len] = 0;
 384
 385        /* Was it a detached head or an old-fashioned symlink? */
 386        if (!get_sha1_hex(buffer, result))
 387                return 0;
 388
 389        /* Symref? */
 390        if (strncmp(buffer, "ref:", 4))
 391                return -1;
 392        p = buffer + 4;
 393        while (isspace(*p))
 394                p++;
 395
 396        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 397}
 398
 399int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 400{
 401        int len = strlen(path), retval;
 402        char *gitdir;
 403        const char *tmp;
 404
 405        while (len && path[len-1] == '/')
 406                len--;
 407        if (!len)
 408                return -1;
 409        gitdir = xmalloc(len + MAXREFLEN + 8);
 410        memcpy(gitdir, path, len);
 411        memcpy(gitdir + len, "/.git", 6);
 412        len += 5;
 413
 414        tmp = read_gitfile_gently(gitdir);
 415        if (tmp) {
 416                free(gitdir);
 417                len = strlen(tmp);
 418                gitdir = xmalloc(len + MAXREFLEN + 3);
 419                memcpy(gitdir, tmp, len);
 420        }
 421        gitdir[len] = '/';
 422        gitdir[++len] = '\0';
 423        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 424        free(gitdir);
 425        return retval;
 426}
 427
 428/*
 429 * If the "reading" argument is set, this function finds out what _object_
 430 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 431 * has to exist, and if it is symbolic, it has to point at an existing ref,
 432 * because the "read" goes through the symref to the ref it points at.
 433 *
 434 * The access that is not "reading" may often be "writing", but does not
 435 * have to; it can be merely checking _where it leads to_. If it is a
 436 * prelude to "writing" to the ref, a write to a symref that points at
 437 * yet-to-be-born ref will create the real ref pointed by the symref.
 438 * reading=0 allows the caller to check where such a symref leads to.
 439 */
 440const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 441{
 442        int depth = MAXDEPTH;
 443        ssize_t len;
 444        char buffer[256];
 445        static char ref_buffer[256];
 446
 447        if (flag)
 448                *flag = 0;
 449
 450        for (;;) {
 451                char path[PATH_MAX];
 452                struct stat st;
 453                char *buf;
 454                int fd;
 455
 456                if (--depth < 0)
 457                        return NULL;
 458
 459                git_snpath(path, sizeof(path), "%s", ref);
 460                /* Special case: non-existing file. */
 461                if (lstat(path, &st) < 0) {
 462                        struct ref_list *list = get_packed_refs();
 463                        while (list) {
 464                                if (!strcmp(ref, list->name)) {
 465                                        hashcpy(sha1, list->sha1);
 466                                        if (flag)
 467                                                *flag |= REF_ISPACKED;
 468                                        return ref;
 469                                }
 470                                list = list->next;
 471                        }
 472                        if (reading || errno != ENOENT)
 473                                return NULL;
 474                        hashclr(sha1);
 475                        return ref;
 476                }
 477
 478                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 479                if (S_ISLNK(st.st_mode)) {
 480                        len = readlink(path, buffer, sizeof(buffer)-1);
 481                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 482                                buffer[len] = 0;
 483                                strcpy(ref_buffer, buffer);
 484                                ref = ref_buffer;
 485                                if (flag)
 486                                        *flag |= REF_ISSYMREF;
 487                                continue;
 488                        }
 489                }
 490
 491                /* Is it a directory? */
 492                if (S_ISDIR(st.st_mode)) {
 493                        errno = EISDIR;
 494                        return NULL;
 495                }
 496
 497                /*
 498                 * Anything else, just open it and try to use it as
 499                 * a ref
 500                 */
 501                fd = open(path, O_RDONLY);
 502                if (fd < 0)
 503                        return NULL;
 504                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 505                close(fd);
 506
 507                /*
 508                 * Is it a symbolic ref?
 509                 */
 510                if (len < 4 || memcmp("ref:", buffer, 4))
 511                        break;
 512                buf = buffer + 4;
 513                len -= 4;
 514                while (len && isspace(*buf))
 515                        buf++, len--;
 516                while (len && isspace(buf[len-1]))
 517                        len--;
 518                buf[len] = 0;
 519                memcpy(ref_buffer, buf, len + 1);
 520                ref = ref_buffer;
 521                if (flag)
 522                        *flag |= REF_ISSYMREF;
 523        }
 524        if (len < 40 || get_sha1_hex(buffer, sha1))
 525                return NULL;
 526        return ref;
 527}
 528
 529/* The argument to filter_refs */
 530struct ref_filter {
 531        const char *pattern;
 532        each_ref_fn *fn;
 533        void *cb_data;
 534};
 535
 536int read_ref(const char *ref, unsigned char *sha1)
 537{
 538        if (resolve_ref(ref, sha1, 1, NULL))
 539                return 0;
 540        return -1;
 541}
 542
 543#define DO_FOR_EACH_INCLUDE_BROKEN 01
 544static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 545                      int flags, void *cb_data, struct ref_list *entry)
 546{
 547        if (strncmp(base, entry->name, trim))
 548                return 0;
 549
 550        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 551                if (entry->flag & REF_BROKEN)
 552                        return 0; /* ignore dangling symref */
 553                if (!has_sha1_file(entry->sha1)) {
 554                        error("%s does not point to a valid object!", entry->name);
 555                        return 0;
 556                }
 557        }
 558        current_ref = entry;
 559        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 560}
 561
 562static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 563        void *data)
 564{
 565        struct ref_filter *filter = (struct ref_filter *)data;
 566        if (fnmatch(filter->pattern, ref, 0))
 567                return 0;
 568        return filter->fn(ref, sha, flags, filter->cb_data);
 569}
 570
 571int peel_ref(const char *ref, unsigned char *sha1)
 572{
 573        int flag;
 574        unsigned char base[20];
 575        struct object *o;
 576
 577        if (current_ref && (current_ref->name == ref
 578                || !strcmp(current_ref->name, ref))) {
 579                if (current_ref->flag & REF_KNOWS_PEELED) {
 580                        hashcpy(sha1, current_ref->peeled);
 581                        return 0;
 582                }
 583                hashcpy(base, current_ref->sha1);
 584                goto fallback;
 585        }
 586
 587        if (!resolve_ref(ref, base, 1, &flag))
 588                return -1;
 589
 590        if ((flag & REF_ISPACKED)) {
 591                struct ref_list *list = get_packed_refs();
 592
 593                while (list) {
 594                        if (!strcmp(list->name, ref)) {
 595                                if (list->flag & REF_KNOWS_PEELED) {
 596                                        hashcpy(sha1, list->peeled);
 597                                        return 0;
 598                                }
 599                                /* older pack-refs did not leave peeled ones */
 600                                break;
 601                        }
 602                        list = list->next;
 603                }
 604        }
 605
 606fallback:
 607        o = parse_object(base);
 608        if (o && o->type == OBJ_TAG) {
 609                o = deref_tag(o, ref, 0);
 610                if (o) {
 611                        hashcpy(sha1, o->sha1);
 612                        return 0;
 613                }
 614        }
 615        return -1;
 616}
 617
 618static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 619                           int flags, void *cb_data)
 620{
 621        int retval = 0;
 622        struct ref_list *packed = get_packed_refs();
 623        struct ref_list *loose = get_loose_refs();
 624
 625        struct ref_list *extra;
 626
 627        for (extra = extra_refs; extra; extra = extra->next)
 628                retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 629
 630        while (packed && loose) {
 631                struct ref_list *entry;
 632                int cmp = strcmp(packed->name, loose->name);
 633                if (!cmp) {
 634                        packed = packed->next;
 635                        continue;
 636                }
 637                if (cmp > 0) {
 638                        entry = loose;
 639                        loose = loose->next;
 640                } else {
 641                        entry = packed;
 642                        packed = packed->next;
 643                }
 644                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 645                if (retval)
 646                        goto end_each;
 647        }
 648
 649        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 650                retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 651                if (retval)
 652                        goto end_each;
 653        }
 654
 655end_each:
 656        current_ref = NULL;
 657        return retval;
 658}
 659
 660int head_ref(each_ref_fn fn, void *cb_data)
 661{
 662        unsigned char sha1[20];
 663        int flag;
 664
 665        if (resolve_ref("HEAD", sha1, 1, &flag))
 666                return fn("HEAD", sha1, flag, cb_data);
 667        return 0;
 668}
 669
 670int for_each_ref(each_ref_fn fn, void *cb_data)
 671{
 672        return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 673}
 674
 675int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 676{
 677        return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
 678}
 679
 680int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 681{
 682        return for_each_ref_in("refs/tags/", fn, cb_data);
 683}
 684
 685int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 686{
 687        return for_each_ref_in("refs/heads/", fn, cb_data);
 688}
 689
 690int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 691{
 692        return for_each_ref_in("refs/remotes/", fn, cb_data);
 693}
 694
 695int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 696{
 697        return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 698}
 699
 700int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 701        const char *prefix, void *cb_data)
 702{
 703        struct strbuf real_pattern = STRBUF_INIT;
 704        struct ref_filter filter;
 705        int ret;
 706
 707        if (!prefix && prefixcmp(pattern, "refs/"))
 708                strbuf_addstr(&real_pattern, "refs/");
 709        else if (prefix)
 710                strbuf_addstr(&real_pattern, prefix);
 711        strbuf_addstr(&real_pattern, pattern);
 712
 713        if (!has_glob_specials(pattern)) {
 714                /* Append implied '/' '*' if not present. */
 715                if (real_pattern.buf[real_pattern.len - 1] != '/')
 716                        strbuf_addch(&real_pattern, '/');
 717                /* No need to check for '*', there is none. */
 718                strbuf_addch(&real_pattern, '*');
 719        }
 720
 721        filter.pattern = real_pattern.buf;
 722        filter.fn = fn;
 723        filter.cb_data = cb_data;
 724        ret = for_each_ref(filter_refs, &filter);
 725
 726        strbuf_release(&real_pattern);
 727        return ret;
 728}
 729
 730int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 731{
 732        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 733}
 734
 735int for_each_rawref(each_ref_fn fn, void *cb_data)
 736{
 737        return do_for_each_ref("refs/", fn, 0,
 738                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 739}
 740
 741/*
 742 * Make sure "ref" is something reasonable to have under ".git/refs/";
 743 * We do not like it if:
 744 *
 745 * - any path component of it begins with ".", or
 746 * - it has double dots "..", or
 747 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 748 * - it ends with a "/".
 749 * - it ends with ".lock"
 750 * - it contains a "\" (backslash)
 751 */
 752
 753static inline int bad_ref_char(int ch)
 754{
 755        if (((unsigned) ch) <= ' ' ||
 756            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 757                return 1;
 758        /* 2.13 Pattern Matching Notation */
 759        if (ch == '?' || ch == '[') /* Unsupported */
 760                return 1;
 761        if (ch == '*') /* Supported at the end */
 762                return 2;
 763        return 0;
 764}
 765
 766int check_ref_format(const char *ref)
 767{
 768        int ch, level, bad_type, last;
 769        int ret = CHECK_REF_FORMAT_OK;
 770        const char *cp = ref;
 771
 772        level = 0;
 773        while (1) {
 774                while ((ch = *cp++) == '/')
 775                        ; /* tolerate duplicated slashes */
 776                if (!ch)
 777                        /* should not end with slashes */
 778                        return CHECK_REF_FORMAT_ERROR;
 779
 780                /* we are at the beginning of the path component */
 781                if (ch == '.')
 782                        return CHECK_REF_FORMAT_ERROR;
 783                bad_type = bad_ref_char(ch);
 784                if (bad_type) {
 785                        if (bad_type == 2 && (!*cp || *cp == '/') &&
 786                            ret == CHECK_REF_FORMAT_OK)
 787                                ret = CHECK_REF_FORMAT_WILDCARD;
 788                        else
 789                                return CHECK_REF_FORMAT_ERROR;
 790                }
 791
 792                last = ch;
 793                /* scan the rest of the path component */
 794                while ((ch = *cp++) != 0) {
 795                        bad_type = bad_ref_char(ch);
 796                        if (bad_type)
 797                                return CHECK_REF_FORMAT_ERROR;
 798                        if (ch == '/')
 799                                break;
 800                        if (last == '.' && ch == '.')
 801                                return CHECK_REF_FORMAT_ERROR;
 802                        if (last == '@' && ch == '{')
 803                                return CHECK_REF_FORMAT_ERROR;
 804                        last = ch;
 805                }
 806                level++;
 807                if (!ch) {
 808                        if (ref <= cp - 2 && cp[-2] == '.')
 809                                return CHECK_REF_FORMAT_ERROR;
 810                        if (level < 2)
 811                                return CHECK_REF_FORMAT_ONELEVEL;
 812                        if (has_extension(ref, ".lock"))
 813                                return CHECK_REF_FORMAT_ERROR;
 814                        return ret;
 815                }
 816        }
 817}
 818
 819const char *prettify_refname(const char *name)
 820{
 821        return name + (
 822                !prefixcmp(name, "refs/heads/") ? 11 :
 823                !prefixcmp(name, "refs/tags/") ? 10 :
 824                !prefixcmp(name, "refs/remotes/") ? 13 :
 825                0);
 826}
 827
 828const char *ref_rev_parse_rules[] = {
 829        "%.*s",
 830        "refs/%.*s",
 831        "refs/tags/%.*s",
 832        "refs/heads/%.*s",
 833        "refs/remotes/%.*s",
 834        "refs/remotes/%.*s/HEAD",
 835        NULL
 836};
 837
 838const char *ref_fetch_rules[] = {
 839        "%.*s",
 840        "refs/%.*s",
 841        "refs/heads/%.*s",
 842        NULL
 843};
 844
 845int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 846{
 847        const char **p;
 848        const int abbrev_name_len = strlen(abbrev_name);
 849
 850        for (p = rules; *p; p++) {
 851                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 852                        return 1;
 853                }
 854        }
 855
 856        return 0;
 857}
 858
 859static struct ref_lock *verify_lock(struct ref_lock *lock,
 860        const unsigned char *old_sha1, int mustexist)
 861{
 862        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 863                error("Can't verify ref %s", lock->ref_name);
 864                unlock_ref(lock);
 865                return NULL;
 866        }
 867        if (hashcmp(lock->old_sha1, old_sha1)) {
 868                error("Ref %s is at %s but expected %s", lock->ref_name,
 869                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 870                unlock_ref(lock);
 871                return NULL;
 872        }
 873        return lock;
 874}
 875
 876static int remove_empty_directories(const char *file)
 877{
 878        /* we want to create a file but there is a directory there;
 879         * if that is an empty directory (or a directory that contains
 880         * only empty directories), remove them.
 881         */
 882        struct strbuf path;
 883        int result;
 884
 885        strbuf_init(&path, 20);
 886        strbuf_addstr(&path, file);
 887
 888        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 889
 890        strbuf_release(&path);
 891
 892        return result;
 893}
 894
 895static int is_refname_available(const char *ref, const char *oldref,
 896                                struct ref_list *list, int quiet)
 897{
 898        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 899        while (list) {
 900                /* list->name could be 'foo' or 'foo/bar/baz' */
 901                if (!oldref || strcmp(oldref, list->name)) {
 902                        int len = strlen(list->name);
 903                        int cmplen = (namlen < len) ? namlen : len;
 904                        const char *lead = (namlen < len) ? list->name : ref;
 905                        if (!strncmp(ref, list->name, cmplen) &&
 906                            lead[cmplen] == '/') {
 907                                if (!quiet)
 908                                        error("'%s' exists; cannot create '%s'",
 909                                              list->name, ref);
 910                                return 0;
 911                        }
 912                }
 913                list = list->next;
 914        }
 915        return 1;
 916}
 917
 918static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 919{
 920        char *ref_file;
 921        const char *orig_ref = ref;
 922        struct ref_lock *lock;
 923        int last_errno = 0;
 924        int type, lflags;
 925        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 926        int missing = 0;
 927
 928        lock = xcalloc(1, sizeof(struct ref_lock));
 929        lock->lock_fd = -1;
 930
 931        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 932        if (!ref && errno == EISDIR) {
 933                /* we are trying to lock foo but we used to
 934                 * have foo/bar which now does not exist;
 935                 * it is normal for the empty directory 'foo'
 936                 * to remain.
 937                 */
 938                ref_file = git_path("%s", orig_ref);
 939                if (remove_empty_directories(ref_file)) {
 940                        last_errno = errno;
 941                        error("there are still refs under '%s'", orig_ref);
 942                        goto error_return;
 943                }
 944                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 945        }
 946        if (type_p)
 947            *type_p = type;
 948        if (!ref) {
 949                last_errno = errno;
 950                error("unable to resolve reference %s: %s",
 951                        orig_ref, strerror(errno));
 952                goto error_return;
 953        }
 954        missing = is_null_sha1(lock->old_sha1);
 955        /* When the ref did not exist and we are creating it,
 956         * make sure there is no existing ref that is packed
 957         * whose name begins with our refname, nor a ref whose
 958         * name is a proper prefix of our refname.
 959         */
 960        if (missing &&
 961             !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
 962                last_errno = ENOTDIR;
 963                goto error_return;
 964        }
 965
 966        lock->lk = xcalloc(1, sizeof(struct lock_file));
 967
 968        lflags = LOCK_DIE_ON_ERROR;
 969        if (flags & REF_NODEREF) {
 970                ref = orig_ref;
 971                lflags |= LOCK_NODEREF;
 972        }
 973        lock->ref_name = xstrdup(ref);
 974        lock->orig_ref_name = xstrdup(orig_ref);
 975        ref_file = git_path("%s", ref);
 976        if (missing)
 977                lock->force_write = 1;
 978        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 979                lock->force_write = 1;
 980
 981        if (safe_create_leading_directories(ref_file)) {
 982                last_errno = errno;
 983                error("unable to create directory for %s", ref_file);
 984                goto error_return;
 985        }
 986
 987        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 988        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 989
 990 error_return:
 991        unlock_ref(lock);
 992        errno = last_errno;
 993        return NULL;
 994}
 995
 996struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 997{
 998        char refpath[PATH_MAX];
 999        if (check_ref_format(ref))
1000                return NULL;
1001        strcpy(refpath, mkpath("refs/%s", ref));
1002        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1003}
1004
1005struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1006{
1007        switch (check_ref_format(ref)) {
1008        default:
1009                return NULL;
1010        case 0:
1011        case CHECK_REF_FORMAT_ONELEVEL:
1012                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1013        }
1014}
1015
1016static struct lock_file packlock;
1017
1018static int repack_without_ref(const char *refname)
1019{
1020        struct ref_list *list, *packed_ref_list;
1021        int fd;
1022        int found = 0;
1023
1024        packed_ref_list = get_packed_refs();
1025        for (list = packed_ref_list; list; list = list->next) {
1026                if (!strcmp(refname, list->name)) {
1027                        found = 1;
1028                        break;
1029                }
1030        }
1031        if (!found)
1032                return 0;
1033        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1034        if (fd < 0) {
1035                unable_to_lock_error(git_path("packed-refs"), errno);
1036                return error("cannot delete '%s' from packed refs", refname);
1037        }
1038
1039        for (list = packed_ref_list; list; list = list->next) {
1040                char line[PATH_MAX + 100];
1041                int len;
1042
1043                if (!strcmp(refname, list->name))
1044                        continue;
1045                len = snprintf(line, sizeof(line), "%s %s\n",
1046                               sha1_to_hex(list->sha1), list->name);
1047                /* this should not happen but just being defensive */
1048                if (len > sizeof(line))
1049                        die("too long a refname '%s'", list->name);
1050                write_or_die(fd, line, len);
1051        }
1052        return commit_lock_file(&packlock);
1053}
1054
1055int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1056{
1057        struct ref_lock *lock;
1058        int err, i = 0, ret = 0, flag = 0;
1059
1060        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1061        if (!lock)
1062                return 1;
1063        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1064                /* loose */
1065                const char *path;
1066
1067                if (!(delopt & REF_NODEREF)) {
1068                        i = strlen(lock->lk->filename) - 5; /* .lock */
1069                        lock->lk->filename[i] = 0;
1070                        path = lock->lk->filename;
1071                } else {
1072                        path = git_path("%s", refname);
1073                }
1074                err = unlink_or_warn(path);
1075                if (err && errno != ENOENT)
1076                        ret = 1;
1077
1078                if (!(delopt & REF_NODEREF))
1079                        lock->lk->filename[i] = '.';
1080        }
1081        /* removing the loose one could have resurrected an earlier
1082         * packed one.  Also, if it was not loose we need to repack
1083         * without it.
1084         */
1085        ret |= repack_without_ref(refname);
1086
1087        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1088        invalidate_cached_refs();
1089        unlock_ref(lock);
1090        return ret;
1091}
1092
1093int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1094{
1095        static const char renamed_ref[] = "RENAMED-REF";
1096        unsigned char sha1[20], orig_sha1[20];
1097        int flag = 0, logmoved = 0;
1098        struct ref_lock *lock;
1099        struct stat loginfo;
1100        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1101        const char *symref = NULL;
1102
1103        if (log && S_ISLNK(loginfo.st_mode))
1104                return error("reflog for %s is a symlink", oldref);
1105
1106        symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1107        if (flag & REF_ISSYMREF)
1108                return error("refname %s is a symbolic ref, renaming it is not supported",
1109                        oldref);
1110        if (!symref)
1111                return error("refname %s not found", oldref);
1112
1113        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1114                return 1;
1115
1116        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1117                return 1;
1118
1119        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1120        if (!lock)
1121                return error("unable to lock %s", renamed_ref);
1122        lock->force_write = 1;
1123        if (write_ref_sha1(lock, orig_sha1, logmsg))
1124                return error("unable to save current sha1 in %s", renamed_ref);
1125
1126        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1127                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1128                        oldref, strerror(errno));
1129
1130        if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1131                error("unable to delete old %s", oldref);
1132                goto rollback;
1133        }
1134
1135        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1136                if (errno==EISDIR) {
1137                        if (remove_empty_directories(git_path("%s", newref))) {
1138                                error("Directory not empty: %s", newref);
1139                                goto rollback;
1140                        }
1141                } else {
1142                        error("unable to delete existing %s", newref);
1143                        goto rollback;
1144                }
1145        }
1146
1147        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1148                error("unable to create directory for %s", newref);
1149                goto rollback;
1150        }
1151
1152 retry:
1153        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1154                if (errno==EISDIR || errno==ENOTDIR) {
1155                        /*
1156                         * rename(a, b) when b is an existing
1157                         * directory ought to result in ISDIR, but
1158                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1159                         */
1160                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1161                                error("Directory not empty: logs/%s", newref);
1162                                goto rollback;
1163                        }
1164                        goto retry;
1165                } else {
1166                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1167                                newref, strerror(errno));
1168                        goto rollback;
1169                }
1170        }
1171        logmoved = log;
1172
1173        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1174        if (!lock) {
1175                error("unable to lock %s for update", newref);
1176                goto rollback;
1177        }
1178        lock->force_write = 1;
1179        hashcpy(lock->old_sha1, orig_sha1);
1180        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1181                error("unable to write current sha1 into %s", newref);
1182                goto rollback;
1183        }
1184
1185        return 0;
1186
1187 rollback:
1188        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1189        if (!lock) {
1190                error("unable to lock %s for rollback", oldref);
1191                goto rollbacklog;
1192        }
1193
1194        lock->force_write = 1;
1195        flag = log_all_ref_updates;
1196        log_all_ref_updates = 0;
1197        if (write_ref_sha1(lock, orig_sha1, NULL))
1198                error("unable to write current sha1 into %s", oldref);
1199        log_all_ref_updates = flag;
1200
1201 rollbacklog:
1202        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1203                error("unable to restore logfile %s from %s: %s",
1204                        oldref, newref, strerror(errno));
1205        if (!logmoved && log &&
1206            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1207                error("unable to restore logfile %s from tmp-renamed-log: %s",
1208                        oldref, strerror(errno));
1209
1210        return 1;
1211}
1212
1213int close_ref(struct ref_lock *lock)
1214{
1215        if (close_lock_file(lock->lk))
1216                return -1;
1217        lock->lock_fd = -1;
1218        return 0;
1219}
1220
1221int commit_ref(struct ref_lock *lock)
1222{
1223        if (commit_lock_file(lock->lk))
1224                return -1;
1225        lock->lock_fd = -1;
1226        return 0;
1227}
1228
1229void unlock_ref(struct ref_lock *lock)
1230{
1231        /* Do not free lock->lk -- atexit() still looks at them */
1232        if (lock->lk)
1233                rollback_lock_file(lock->lk);
1234        free(lock->ref_name);
1235        free(lock->orig_ref_name);
1236        free(lock);
1237}
1238
1239/*
1240 * copy the reflog message msg to buf, which has been allocated sufficiently
1241 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1242 * because reflog file is one line per entry.
1243 */
1244static int copy_msg(char *buf, const char *msg)
1245{
1246        char *cp = buf;
1247        char c;
1248        int wasspace = 1;
1249
1250        *cp++ = '\t';
1251        while ((c = *msg++)) {
1252                if (wasspace && isspace(c))
1253                        continue;
1254                wasspace = isspace(c);
1255                if (wasspace)
1256                        c = ' ';
1257                *cp++ = c;
1258        }
1259        while (buf < cp && isspace(cp[-1]))
1260                cp--;
1261        *cp++ = '\n';
1262        return cp - buf;
1263}
1264
1265int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1266{
1267        int logfd, oflags = O_APPEND | O_WRONLY;
1268
1269        git_snpath(logfile, bufsize, "logs/%s", ref_name);
1270        if (log_all_ref_updates &&
1271            (!prefixcmp(ref_name, "refs/heads/") ||
1272             !prefixcmp(ref_name, "refs/remotes/") ||
1273             !prefixcmp(ref_name, "refs/notes/") ||
1274             !strcmp(ref_name, "HEAD"))) {
1275                if (safe_create_leading_directories(logfile) < 0)
1276                        return error("unable to create directory for %s",
1277                                     logfile);
1278                oflags |= O_CREAT;
1279        }
1280
1281        logfd = open(logfile, oflags, 0666);
1282        if (logfd < 0) {
1283                if (!(oflags & O_CREAT) && errno == ENOENT)
1284                        return 0;
1285
1286                if ((oflags & O_CREAT) && errno == EISDIR) {
1287                        if (remove_empty_directories(logfile)) {
1288                                return error("There are still logs under '%s'",
1289                                             logfile);
1290                        }
1291                        logfd = open(logfile, oflags, 0666);
1292                }
1293
1294                if (logfd < 0)
1295                        return error("Unable to append to %s: %s",
1296                                     logfile, strerror(errno));
1297        }
1298
1299        adjust_shared_perm(logfile);
1300        close(logfd);
1301        return 0;
1302}
1303
1304static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1305                         const unsigned char *new_sha1, const char *msg)
1306{
1307        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1308        unsigned maxlen, len;
1309        int msglen;
1310        char log_file[PATH_MAX];
1311        char *logrec;
1312        const char *committer;
1313
1314        if (log_all_ref_updates < 0)
1315                log_all_ref_updates = !is_bare_repository();
1316
1317        result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1318        if (result)
1319                return result;
1320
1321        logfd = open(log_file, oflags);
1322        if (logfd < 0)
1323                return 0;
1324        msglen = msg ? strlen(msg) : 0;
1325        committer = git_committer_info(0);
1326        maxlen = strlen(committer) + msglen + 100;
1327        logrec = xmalloc(maxlen);
1328        len = sprintf(logrec, "%s %s %s\n",
1329                      sha1_to_hex(old_sha1),
1330                      sha1_to_hex(new_sha1),
1331                      committer);
1332        if (msglen)
1333                len += copy_msg(logrec + len - 1, msg) - 1;
1334        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1335        free(logrec);
1336        if (close(logfd) != 0 || written != len)
1337                return error("Unable to append to %s", log_file);
1338        return 0;
1339}
1340
1341static int is_branch(const char *refname)
1342{
1343        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1344}
1345
1346int write_ref_sha1(struct ref_lock *lock,
1347        const unsigned char *sha1, const char *logmsg)
1348{
1349        static char term = '\n';
1350        struct object *o;
1351
1352        if (!lock)
1353                return -1;
1354        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1355                unlock_ref(lock);
1356                return 0;
1357        }
1358        o = parse_object(sha1);
1359        if (!o) {
1360                error("Trying to write ref %s with nonexistant object %s",
1361                        lock->ref_name, sha1_to_hex(sha1));
1362                unlock_ref(lock);
1363                return -1;
1364        }
1365        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1366                error("Trying to write non-commit object %s to branch %s",
1367                        sha1_to_hex(sha1), lock->ref_name);
1368                unlock_ref(lock);
1369                return -1;
1370        }
1371        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1372            write_in_full(lock->lock_fd, &term, 1) != 1
1373                || close_ref(lock) < 0) {
1374                error("Couldn't write %s", lock->lk->filename);
1375                unlock_ref(lock);
1376                return -1;
1377        }
1378        invalidate_cached_refs();
1379        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1380            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1381             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1382                unlock_ref(lock);
1383                return -1;
1384        }
1385        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1386                /*
1387                 * Special hack: If a branch is updated directly and HEAD
1388                 * points to it (may happen on the remote side of a push
1389                 * for example) then logically the HEAD reflog should be
1390                 * updated too.
1391                 * A generic solution implies reverse symref information,
1392                 * but finding all symrefs pointing to the given branch
1393                 * would be rather costly for this rare event (the direct
1394                 * update of a branch) to be worth it.  So let's cheat and
1395                 * check with HEAD only which should cover 99% of all usage
1396                 * scenarios (even 100% of the default ones).
1397                 */
1398                unsigned char head_sha1[20];
1399                int head_flag;
1400                const char *head_ref;
1401                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1402                if (head_ref && (head_flag & REF_ISSYMREF) &&
1403                    !strcmp(head_ref, lock->ref_name))
1404                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1405        }
1406        if (commit_ref(lock)) {
1407                error("Couldn't set %s", lock->ref_name);
1408                unlock_ref(lock);
1409                return -1;
1410        }
1411        unlock_ref(lock);
1412        return 0;
1413}
1414
1415int create_symref(const char *ref_target, const char *refs_heads_master,
1416                  const char *logmsg)
1417{
1418        const char *lockpath;
1419        char ref[1000];
1420        int fd, len, written;
1421        char *git_HEAD = git_pathdup("%s", ref_target);
1422        unsigned char old_sha1[20], new_sha1[20];
1423
1424        if (logmsg && read_ref(ref_target, old_sha1))
1425                hashclr(old_sha1);
1426
1427        if (safe_create_leading_directories(git_HEAD) < 0)
1428                return error("unable to create directory for %s", git_HEAD);
1429
1430#ifndef NO_SYMLINK_HEAD
1431        if (prefer_symlink_refs) {
1432                unlink(git_HEAD);
1433                if (!symlink(refs_heads_master, git_HEAD))
1434                        goto done;
1435                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1436        }
1437#endif
1438
1439        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1440        if (sizeof(ref) <= len) {
1441                error("refname too long: %s", refs_heads_master);
1442                goto error_free_return;
1443        }
1444        lockpath = mkpath("%s.lock", git_HEAD);
1445        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1446        if (fd < 0) {
1447                error("Unable to open %s for writing", lockpath);
1448                goto error_free_return;
1449        }
1450        written = write_in_full(fd, ref, len);
1451        if (close(fd) != 0 || written != len) {
1452                error("Unable to write to %s", lockpath);
1453                goto error_unlink_return;
1454        }
1455        if (rename(lockpath, git_HEAD) < 0) {
1456                error("Unable to create %s", git_HEAD);
1457                goto error_unlink_return;
1458        }
1459        if (adjust_shared_perm(git_HEAD)) {
1460                error("Unable to fix permissions on %s", lockpath);
1461        error_unlink_return:
1462                unlink_or_warn(lockpath);
1463        error_free_return:
1464                free(git_HEAD);
1465                return -1;
1466        }
1467
1468#ifndef NO_SYMLINK_HEAD
1469        done:
1470#endif
1471        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1472                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1473
1474        free(git_HEAD);
1475        return 0;
1476}
1477
1478static char *ref_msg(const char *line, const char *endp)
1479{
1480        const char *ep;
1481        line += 82;
1482        ep = memchr(line, '\n', endp - line);
1483        if (!ep)
1484                ep = endp;
1485        return xmemdupz(line, ep - line);
1486}
1487
1488int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1, char **msg, unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1489{
1490        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1491        char *tz_c;
1492        int logfd, tz, reccnt = 0;
1493        struct stat st;
1494        unsigned long date;
1495        unsigned char logged_sha1[20];
1496        void *log_mapped;
1497        size_t mapsz;
1498
1499        logfile = git_path("logs/%s", ref);
1500        logfd = open(logfile, O_RDONLY, 0);
1501        if (logfd < 0)
1502                die_errno("Unable to read log '%s'", logfile);
1503        fstat(logfd, &st);
1504        if (!st.st_size)
1505                die("Log %s is empty.", logfile);
1506        mapsz = xsize_t(st.st_size);
1507        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1508        logdata = log_mapped;
1509        close(logfd);
1510
1511        lastrec = NULL;
1512        rec = logend = logdata + st.st_size;
1513        while (logdata < rec) {
1514                reccnt++;
1515                if (logdata < rec && *(rec-1) == '\n')
1516                        rec--;
1517                lastgt = NULL;
1518                while (logdata < rec && *(rec-1) != '\n') {
1519                        rec--;
1520                        if (*rec == '>')
1521                                lastgt = rec;
1522                }
1523                if (!lastgt)
1524                        die("Log %s is corrupt.", logfile);
1525                date = strtoul(lastgt + 1, &tz_c, 10);
1526                if (date <= at_time || cnt == 0) {
1527                        tz = strtoul(tz_c, NULL, 10);
1528                        if (msg)
1529                                *msg = ref_msg(rec, logend);
1530                        if (cutoff_time)
1531                                *cutoff_time = date;
1532                        if (cutoff_tz)
1533                                *cutoff_tz = tz;
1534                        if (cutoff_cnt)
1535                                *cutoff_cnt = reccnt - 1;
1536                        if (lastrec) {
1537                                if (get_sha1_hex(lastrec, logged_sha1))
1538                                        die("Log %s is corrupt.", logfile);
1539                                if (get_sha1_hex(rec + 41, sha1))
1540                                        die("Log %s is corrupt.", logfile);
1541                                if (hashcmp(logged_sha1, sha1)) {
1542                                        warning("Log %s has gap after %s.",
1543                                                logfile, show_date(date, tz, DATE_RFC2822));
1544                                }
1545                        }
1546                        else if (date == at_time) {
1547                                if (get_sha1_hex(rec + 41, sha1))
1548                                        die("Log %s is corrupt.", logfile);
1549                        }
1550                        else {
1551                                if (get_sha1_hex(rec + 41, logged_sha1))
1552                                        die("Log %s is corrupt.", logfile);
1553                                if (hashcmp(logged_sha1, sha1)) {
1554                                        warning("Log %s unexpectedly ended on %s.",
1555                                                logfile, show_date(date, tz, DATE_RFC2822));
1556                                }
1557                        }
1558                        munmap(log_mapped, mapsz);
1559                        return 0;
1560                }
1561                lastrec = rec;
1562                if (cnt > 0)
1563                        cnt--;
1564        }
1565
1566        rec = logdata;
1567        while (rec < logend && *rec != '>' && *rec != '\n')
1568                rec++;
1569        if (rec == logend || *rec == '\n')
1570                die("Log %s is corrupt.", logfile);
1571        date = strtoul(rec + 1, &tz_c, 10);
1572        tz = strtoul(tz_c, NULL, 10);
1573        if (get_sha1_hex(logdata, sha1))
1574                die("Log %s is corrupt.", logfile);
1575        if (is_null_sha1(sha1)) {
1576                if (get_sha1_hex(logdata + 41, sha1))
1577                        die("Log %s is corrupt.", logfile);
1578        }
1579        if (msg)
1580                *msg = ref_msg(logdata, logend);
1581        munmap(log_mapped, mapsz);
1582
1583        if (cutoff_time)
1584                *cutoff_time = date;
1585        if (cutoff_tz)
1586                *cutoff_tz = tz;
1587        if (cutoff_cnt)
1588                *cutoff_cnt = reccnt;
1589        return 1;
1590}
1591
1592int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1593{
1594        const char *logfile;
1595        FILE *logfp;
1596        struct strbuf sb = STRBUF_INIT;
1597        int ret = 0;
1598
1599        logfile = git_path("logs/%s", ref);
1600        logfp = fopen(logfile, "r");
1601        if (!logfp)
1602                return -1;
1603
1604        if (ofs) {
1605                struct stat statbuf;
1606                if (fstat(fileno(logfp), &statbuf) ||
1607                    statbuf.st_size < ofs ||
1608                    fseek(logfp, -ofs, SEEK_END) ||
1609                    strbuf_getwholeline(&sb, logfp, '\n')) {
1610                        fclose(logfp);
1611                        strbuf_release(&sb);
1612                        return -1;
1613                }
1614        }
1615
1616        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1617                unsigned char osha1[20], nsha1[20];
1618                char *email_end, *message;
1619                unsigned long timestamp;
1620                int tz;
1621
1622                /* old SP new SP name <email> SP time TAB msg LF */
1623                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1624                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1625                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1626                    !(email_end = strchr(sb.buf + 82, '>')) ||
1627                    email_end[1] != ' ' ||
1628                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1629                    !message || message[0] != ' ' ||
1630                    (message[1] != '+' && message[1] != '-') ||
1631                    !isdigit(message[2]) || !isdigit(message[3]) ||
1632                    !isdigit(message[4]) || !isdigit(message[5]))
1633                        continue; /* corrupt? */
1634                email_end[1] = '\0';
1635                tz = strtol(message + 1, NULL, 10);
1636                if (message[6] != '\t')
1637                        message += 6;
1638                else
1639                        message += 7;
1640                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1641                         cb_data);
1642                if (ret)
1643                        break;
1644        }
1645        fclose(logfp);
1646        strbuf_release(&sb);
1647        return ret;
1648}
1649
1650int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1651{
1652        return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1653}
1654
1655static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1656{
1657        DIR *dir = opendir(git_path("logs/%s", base));
1658        int retval = 0;
1659
1660        if (dir) {
1661                struct dirent *de;
1662                int baselen = strlen(base);
1663                char *log = xmalloc(baselen + 257);
1664
1665                memcpy(log, base, baselen);
1666                if (baselen && base[baselen-1] != '/')
1667                        log[baselen++] = '/';
1668
1669                while ((de = readdir(dir)) != NULL) {
1670                        struct stat st;
1671                        int namelen;
1672
1673                        if (de->d_name[0] == '.')
1674                                continue;
1675                        namelen = strlen(de->d_name);
1676                        if (namelen > 255)
1677                                continue;
1678                        if (has_extension(de->d_name, ".lock"))
1679                                continue;
1680                        memcpy(log + baselen, de->d_name, namelen+1);
1681                        if (stat(git_path("logs/%s", log), &st) < 0)
1682                                continue;
1683                        if (S_ISDIR(st.st_mode)) {
1684                                retval = do_for_each_reflog(log, fn, cb_data);
1685                        } else {
1686                                unsigned char sha1[20];
1687                                if (!resolve_ref(log, sha1, 0, NULL))
1688                                        retval = error("bad ref for %s", log);
1689                                else
1690                                        retval = fn(log, sha1, 0, cb_data);
1691                        }
1692                        if (retval)
1693                                break;
1694                }
1695                free(log);
1696                closedir(dir);
1697        }
1698        else if (*base)
1699                return errno;
1700        return retval;
1701}
1702
1703int for_each_reflog(each_ref_fn fn, void *cb_data)
1704{
1705        return do_for_each_reflog("", fn, cb_data);
1706}
1707
1708int update_ref(const char *action, const char *refname,
1709                const unsigned char *sha1, const unsigned char *oldval,
1710                int flags, enum action_on_err onerr)
1711{
1712        static struct ref_lock *lock;
1713        lock = lock_any_ref_for_update(refname, oldval, flags);
1714        if (!lock) {
1715                const char *str = "Cannot lock the ref '%s'.";
1716                switch (onerr) {
1717                case MSG_ON_ERR: error(str, refname); break;
1718                case DIE_ON_ERR: die(str, refname); break;
1719                case QUIET_ON_ERR: break;
1720                }
1721                return 1;
1722        }
1723        if (write_ref_sha1(lock, sha1, action) < 0) {
1724                const char *str = "Cannot update the ref '%s'.";
1725                switch (onerr) {
1726                case MSG_ON_ERR: error(str, refname); break;
1727                case DIE_ON_ERR: die(str, refname); break;
1728                case QUIET_ON_ERR: break;
1729                }
1730                return 1;
1731        }
1732        return 0;
1733}
1734
1735struct ref *find_ref_by_name(const struct ref *list, const char *name)
1736{
1737        for ( ; list; list = list->next)
1738                if (!strcmp(list->name, name))
1739                        return (struct ref *)list;
1740        return NULL;
1741}
1742
1743/*
1744 * generate a format suitable for scanf from a ref_rev_parse_rules
1745 * rule, that is replace the "%.*s" spec with a "%s" spec
1746 */
1747static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1748{
1749        char *spec;
1750
1751        spec = strstr(rule, "%.*s");
1752        if (!spec || strstr(spec + 4, "%.*s"))
1753                die("invalid rule in ref_rev_parse_rules: %s", rule);
1754
1755        /* copy all until spec */
1756        strncpy(scanf_fmt, rule, spec - rule);
1757        scanf_fmt[spec - rule] = '\0';
1758        /* copy new spec */
1759        strcat(scanf_fmt, "%s");
1760        /* copy remaining rule */
1761        strcat(scanf_fmt, spec + 4);
1762
1763        return;
1764}
1765
1766char *shorten_unambiguous_ref(const char *ref, int strict)
1767{
1768        int i;
1769        static char **scanf_fmts;
1770        static int nr_rules;
1771        char *short_name;
1772
1773        /* pre generate scanf formats from ref_rev_parse_rules[] */
1774        if (!nr_rules) {
1775                size_t total_len = 0;
1776
1777                /* the rule list is NULL terminated, count them first */
1778                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1779                        /* no +1 because strlen("%s") < strlen("%.*s") */
1780                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
1781
1782                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1783
1784                total_len = 0;
1785                for (i = 0; i < nr_rules; i++) {
1786                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1787                                        + total_len;
1788                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1789                        total_len += strlen(ref_rev_parse_rules[i]);
1790                }
1791        }
1792
1793        /* bail out if there are no rules */
1794        if (!nr_rules)
1795                return xstrdup(ref);
1796
1797        /* buffer for scanf result, at most ref must fit */
1798        short_name = xstrdup(ref);
1799
1800        /* skip first rule, it will always match */
1801        for (i = nr_rules - 1; i > 0 ; --i) {
1802                int j;
1803                int rules_to_fail = i;
1804                int short_name_len;
1805
1806                if (1 != sscanf(ref, scanf_fmts[i], short_name))
1807                        continue;
1808
1809                short_name_len = strlen(short_name);
1810
1811                /*
1812                 * in strict mode, all (except the matched one) rules
1813                 * must fail to resolve to a valid non-ambiguous ref
1814                 */
1815                if (strict)
1816                        rules_to_fail = nr_rules;
1817
1818                /*
1819                 * check if the short name resolves to a valid ref,
1820                 * but use only rules prior to the matched one
1821                 */
1822                for (j = 0; j < rules_to_fail; j++) {
1823                        const char *rule = ref_rev_parse_rules[j];
1824                        unsigned char short_objectname[20];
1825                        char refname[PATH_MAX];
1826
1827                        /* skip matched rule */
1828                        if (i == j)
1829                                continue;
1830
1831                        /*
1832                         * the short name is ambiguous, if it resolves
1833                         * (with this previous rule) to a valid ref
1834                         * read_ref() returns 0 on success
1835                         */
1836                        mksnpath(refname, sizeof(refname),
1837                                 rule, short_name_len, short_name);
1838                        if (!read_ref(refname, short_objectname))
1839                                break;
1840                }
1841
1842                /*
1843                 * short name is non-ambiguous if all previous rules
1844                 * haven't resolved to a valid ref
1845                 */
1846                if (j == rules_to_fail)
1847                        return short_name;
1848        }
1849
1850        free(short_name);
1851        return xstrdup(ref);
1852}